1. Field of the Invention
This invention relates to hydroxyalkyl polyethylene glycol and hydroxyalkyl polypropylene glycol ethers, to a process for the production of these compounds, and to their use as foam-inhibiting additives in low-foam cleaning preparations.
2. State of Related Art
Aqueous cleaning preparations intended for use in the institutional and industrial sectors, particularly those intended for cleaning metal, glass, ceramic, and plastic surfaces, generally contain compounds which give rise to undesirable foaming under prevailing working conditions, for example, anionic surfactants or nonionic surfactants which foam at the working temperature.To prevent the unwanted foaming, it is thus necessary in almost every instance to add to aqueous cleaning preparations of the above type substances which are capable of preventing, or reducing the tendency toward, unwanted foaming. In most cases, the use of foaminhibiting additives is also necessary because the soils detached from the substrates and collecting in the cleaning liquors from additional foam.
Adducts of alkylene oxides with organic compounds containing reactive hydrogen atoms, preferably several reactive hydrogen atoms, in the molecule have long been successfully used as foaminhibiting additives. Among such products, adducts of propylene oxide with aliphatic polyalcohols (see e.g. U.S. 3,491,029, and German patent 1 621 593) adducts of propylene oxide with aliphatic polyamines (German patents 1 289 579 and 1 621 593) and also adducts of ethylene oxide and propylene oxide with aliphatic polyamines, particularly ethylenediamine. In addition to a good foam-inhibiting effect, these alkylene oxide adducts also show the alkali stability generally required for use in institutional and industrial cleaning preparations. However, compounds of this type are not sufficiently biodegradable and, accordingly, do not satisfy the current legal requirements of some countries (e.g. regulations under German detergent law).